Inequality in Scotland has got worse not better since devolution, according to a new expert study.

Gwilym Pryce, a social statistics professor at the University of Sheffield, has concluded that the gap between the rich and poor in Scotland is widening. Differences in income are now slightly greater than they were 20 years ago, he said.

That means that income inequality in Scotland is getting more like Great Britain as a whole and less like the Nordic countries, he argued – though Scotland still has a lower level of inequality than Britain.

Pryce is due to present his analysis at a conference for understanding inequalities in Glasgow on 8 November. It’s part of a three-year project funded by the Economic and Social Research Council, which he co-chairs.

He described his findings as “surprising” and argued that Scotland had to make “difficult choices” if it was serious about emulating Nordic levels of equality. Options included raising income tax, making better use of devolved powers or independence, he said.

“What motivated our research was that following the introduction of the Scotland Act the Nordic models were talked about as something to be aimed for,” he explained. “We were interested to see if Scottish measurements of equality had improved accordingly.”

Along with Meng Le Zhang, a research associate at the University of Sheffield, Pryce measured the varying impacts of air pollution, crime and housing on affluent and less affluent areas – and concluded that since 2004 Scotland had fared worse than England.

What has surprised us is that Scotland has done worse than England in several measures. Gwylym Pryce, University of Sheffield

“What has surprised us is that Scotland has done worse than England in several measures even though in England there hasn’t been nearly the same emphasis on equality in terms of policy,” he said.

They found that inequality in exposure of air pollution had fallen “significantly” in England but not in Scotland. According to the Royal College of Physicians, air pollution causes 40,000 premature deaths a year in the UK.

They also discovered that inequality in housing quality and exposure to crime had fallen significantly in England but changed little in Scotland.

In an article in The Conversation, Pryce and Le Zhang pointed out that the evidence tended to contradict the political rhetoric and aspiration. “For some measures, things have been improving in England relative to Scotland,” they wrote.

“One of the reasons for this is that there has been a fall in the concentration of poverty in inner cities, partly due to gentrification. This may have helped reduce the inequality in exposure to crime and air pollution, which tend to be higher near the centre of cities, particularly in larger cities in England.”

They argued that their findings raised “tricky questions” for the next 20 years of devolution. “What does Scotland need to do to reduce inequality to the levels of the Nordic countries?” they asked.

They pointed out that in 1999 the Scottish Parliament was given the power to raise income tax by up to 3p in the pound. But even if there were the political will to increase the tax, they questioned whether that would be enough to make any significant progress.

“Or will other factors, such as the suburbanisation of poverty – where poorer people are pushed out to the periphery of cities – dominate the experience of inequality? It seems likely that more radical changes, such as significant redistribution of income, labour market reforms and major investment in deprived areas, would be needed to bring Scottish inequality close to Nordic levels,” Pryce and Le Zhang argued.

“But is there really an appetite for such reform? And then there’s the trickiest question of all: is the only realistic way for Scotland to pursue the Nordic nirvana to become fully independent?”

Pryce’s conference presentation in Glasgow will suggest that devolving more power at a local level might help address inequality in urban centres.

Claim wealth inequality in Scotland has increased is True

Scottish Labour blamed “Tory austerity and SNP complacency” for “scandalous” levels of poverty in Scotland. “Only radical Labour governments at Holyrood and Westminster can transform our broken economy so it works for the many, not the few,” said the party’s spokesperson for the eradication of poverty and inequality, Elaine Smith MSP.

The Scottish Government stressed that tackling inequalities was at the heart of everything it did. “We are committed to making Scotland a fairer, more equal country,” said a government spokesperson.

“Our Every Child, Every Chance plan sets out concrete actions to help eradicate child poverty by 2030 and includes the £50 million tackling child poverty fund. We are committed to fair work, including paying the living wage, excluding exploitative zero-hours contracts and being transparent on gender-equal pay. In the next three years, we will be working to lift at least 25,000 more people onto the living wage through our work to build a living wage nation.”

According to the Scottish Government, Scotland is the best performing of all the UK countries in terms of paying the living wage, with the highest proportion of employees – 81.6 per cent – paid the living wage or more.